Theses and Dissertations at Montana State University (MSU)
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Item Bullion Creek and Sentinel Butte formations: a study of relative dating and specimen descriptions from near Cartwright, North Dakota(Montana State University - Bozeman, College of Letters & Science, 2022) Graham, Veronica Noel; Chairperson, Graduate Committee: C. John GravesMakenzie County in North Dakota, especially near Cartwright has not been explored by paleontologists for some time and never in great detail, yet the area is full evidence of the past. This paper focuses on the period of time between 50 and 65 million years ago when the area was believed to be a swampy sub-tropical forest skirting an inner continental seaway. It is the purpose of this paper to determine, through rock description and fossil leaf identification, the formation or formations present in this area of focus. These formations will in-turn pinpoint the time period in which the exposures were deposited. Identification of leaf impressions and molds are based on 9 key identifiers; lamina width and length, type of margin, lobation, apex and base type, apex and base angle, and vein pattern. Fossil leaf specimens can be identified to the class Magnoliopsida and other family levels, such as Taxodiaceae, Ulmaceae, Alismaceae, Betulaceae, and Sabiaceae. Additionally, some leaf specimens can be identified to the genus and species levels, including Metasequoia occidentalis, Ulmites microphylla, Alismaphyllites grandifolius, Meliosma vandaelium, and Corylus insignis. Fossils were collected on private land just outside Cartwright North Dakota where they were prepped for transport. In the lab setting they were cleaned, cataloged, and identified for the purpose of relative dating. These results demonstrate that both Sentinel Butte and Bullion Creek formations are present in the study area.Item An analysis of fossil identification guides to improve data reporting in citizen science programs(Montana State University - Bozeman, College of Letters & Science, 2018) Butler, Dava; Chairperson, Graduate Committee: Greg FrancisAn increasing number of organizations use untrained volunteers to gather scientific data. This citizen science movement builds enthusiasm for science by engaging the public, as well as providing a way to gather large amounts of information at little or no expense. The challenge of citizen science is obtaining accurate information from participants. Identifying an image style that increases correct identifications helps not only the citizen science movement but also scientific instruction in general. This study tests three visual guides for identifying late Hemphillian (5-4.5 m.y.a.) fossils from Polk County, Florida. Each guide has identical layout and text, differing only in image style: color photos, grayscale photos, or illustrations. Teams of untrained participants each use one guide to identify fossils. Geology and paleontology professionals also identify fossils for comparison. Comparing results reveals that photographic images, either color or grayscale, produce results most similar to data from professionals.Item The evolution of reproduction within Testudinata as evidenced by the fossil record(Montana State University - Bozeman, College of Letters & Science, 2017) Lawver, Daniel Ryan; Chairperson, Graduate Committee: Frankie Jackson; David Varricchio (co-chair); Frankie D. Jackson was a co-author of the article, 'A review of the fossil record of turtle reprodution: eggs, embryos, nests, and copulating pairs' in the journal 'Bulletin of the Peabody Museum of Natural History' which is contained within this thesis.; Armand H. Rasoamiaramanana and Ingmar Werneburg were co-authors of the article, 'An occurrence of fossil eggs from the Mesozoic of Madagascar and a detailed observation of eggshell microstructure' in the journal 'Journal of vertebrate paleontology' which is contained within this thesis.; Frankie D. Jackson was a co-author of the article, 'An accumulation of turtle eggs with embryos from the Campanian (upper Cretaceous) Judith River Formation of Montana' in the journal 'Cretaceous research' which is contained within this thesis.; Frankie D. Jackson was a co-author of the article, 'A fossil egg clutch from the stem turtle Meiolania platyceps: implications for the evolution of turtle reproductive biology' in the journal 'Journal of vertebrate paleontology' which is contained within this thesis.Although known from every continent except Antarctica and having a fossil record ranging from the Middle Jurassic to the Pleistocene, fossil turtle eggs are relatively understudied. In this dissertation I describe four fossil specimens, interpret paleoecology and conduct cladistic analyses in order to investigate the evolution of turtle reproduction. Fossil eggshell descriptions primarily involve analysis by scanning electron and polarized light microscopy, as well as cathodoluminescence to determine the degree of diagenetic alteration. Carapace lengths and gas conductance are estimated in order to investigate the ecology of the adults that produced fossil turtle eggs and clutches, as well as their incubation environments, respectively. Cladistic analyses of turtle egg and reproductive characters permit assessment of the usefulness of these characters for determining phylogenetic relationships of fossil specimens and the evolution of reproduction in turtles. Specimens described here include 1) Testudoolithus oosp. from the Late Cretaceous of Madagascar, 2) a clutch of eggs (some containing late stage embryos and at least one exhibiting multilayer eggshell) from the Late Cretaceous Judith River Formation of Montana and named Testudoolithus zelenitskyae oosp. nov., 3) an egg contained within an adult Basilemys nobilis from the Late Cretaceous Kaiparowits Formation of Utah, and 4) a clutch of Meiolania platyceps eggs from the Pleistocene of Lord Howe Island, Australia. Meiolania platyceps eggs are named Testudoolithus lordhowensis oosp. nov. and provide valuable information on the origin of aragonite eggshell composition and nesting behaviors. Cladistic analyses utilizing egg and reproductive characters are rarely performed on taxa outside of Dinosauria. My analyses demonstrate that morphological data produces poorly resolved trees in which only the clades Adocia and Trionychia are resolved and all other turtles form a large polytomy. However, when combined with molecular data, egg and reproductive characters have more resolving potential towards the top of trees. This poor resolution is likely due to homoplasy in the form of character reversals, convergent evolution, and/or from the limited number of informative characters.Item Paleoenvironment and taphonomy of the fauna of the Tullock Formation (early Paleocene), McGuire Creek area, McCone County, Montana(Montana State University - Bozeman, College of Letters & Science, 1992) Katsura, YoshihiroItem Microstructural, elemental and biomolecular preservation of Tyrannosaurus rex cancellous tissues(Montana State University - Bozeman, College of Letters & Science, 1995) Schweitzer, Mary Higby; Chairperson, Graduate Committee: John R. Horner; Robert E. Moore (co-chair)Item Verification of von Ebner incremental lines in extant and fossil archosaur dentine and tooth replacement rate assessment using counts of von Ebner lines(Montana State University - Bozeman, College of Letters & Science, 1992) Erickson, Gregory MarkItem Fossil eggs and perinatal remains from the upper Cretaceous Two Medicine Formation of Montana : description and implications(Montana State University - Bozeman, College of Letters & Science, 2014) Oser, Sara Elizabeth; Co-chairpersons, Graduate Committee: Frankie Jackson and David Varricchio; Frankie D. Jackson was a co-author of the article, 'Sediment and eggshell interactions: using abrasion to assess transport in fossil eggshell accumulations' in the journal 'Historical biology' which is contained within this thesis.Egg Mountain is a dinosaur nesting site located in the Upper Cretaceous, Two Medicine Formation of western Montana. The site was located on a coastal plain with seasonal variations in rainfall and was utilized as a nesting location by several taxa. Egg Mountain hosts a remarkable diversity of fossil eggshell and is a window into the reproductive behavior of multiple extinct taxa. A recent 4x6 m excavation revealed two clusters of unidentified eggs, 185 Spheroolithus eggshell fragments, and perinatal osteological remains within homogenous siliciclastic mudstone. Insect burrows (Celliforma) and cocoons (Rebuffoichnus) were excavated from the micritic limestone bed capping the excavation. The objectives of this thesis are to 1) describe the eggs and eggshell fragments, 2) determine nesting environment, 3) assign the osteological remains to taxon, and 4) investigate the taphonomic history of the site. Analytical methods include scanning electron microscopy, cathodoluminescence, petrographic microscopy, and ImageJ photo analysis. The lithologically compressed, unidentified 12 cm diameter eggs occur in two clusters containing 7-22 eggs. Diagenetic alteration obscures eggshell microstructure, inhibiting ootaxonomic assignment of the 0.5 mm thick eggshell. The 0.8-1.3 mm thick fragmentary eggshell is assigned to Spheroolithus albertensis based on microstructure, sagenotuberculate ornamentation, and prolatocanaliculate/ rimocanaliculate pores. To assess taphonomic history of the Spheroolithus fragments, chicken (Gallus gallus domesticus) and ostrich (Struthio camelus) eggshells were placed in a tumbler with water and quartz sand to simulate transport. The resulting wear on these fragments was compared to unabraded eggshell. In addition, modern eggshell was compared to fossil eggshells from a fossil nesting site, crevasse splay and channel deposits, and Egg Mountain. Spheroolithus eggshell from Egg Mountain lack edge rounding and resemble fossil eggshell from a nesting site and unabraded modern eggshell, suggesting a parautochthonous assemblage. Spheroolithus and unidentified eggs from cluster 1 respectively have gas conductance values 16-32x and 4-13x higher than avian eggs of the same mass, suggesting enclosed nest environments. The morphology of the humerus and skull elements of the perinatal osteological remains is consistent with the Hadrosauridae, though the juvenile status and incomplete nature of the specimen inhibits further taxonomic assignment.Item Scratch-digging in the Cretaceous basal ornithopod dinosaur Oryctodromeus cubicularis : evidence from morphometric analyses and reconstruction of the forelimb musculature(Montana State University - Bozeman, College of Letters & Science, 2013) Fearon, Jamie Lynn; Chairperson, Graduate Committee: David Varricchio; David J. Varricchio was a co-author of the article, 'Morphometric analysis of the forelimb and pectoral girdle of the Cretaceous ornithopod dinosaur Oryctodromeus cubicularis and implications for digging' submitted to the journal 'Journal of vertebrate paleontology' which is contained within this thesis.; David J. Varricchio was a co-author of the article, 'Reconstruction of the forelimb musculature of the Cretaceous ornithopod dinosaur Oryctodromeus cubicularis: implications for digging' submitted to the journal 'Journal of vertebrate paleontology' which is contained within this thesis.The basal ornithopod dinosaur Oryctodromeus cubicularis was discovered within a burrow structure in the mid-Cretaceous Blackleaf Formation of western Montana. This, and features of the pelvis, skull, and forelimbs also seen in burrowing mammals led to the interpretation of Oryctodromeus as the first formally described burrowing dinosaur. This study further describes the forelimb specialization of Oryctodromeus and analyzes the validity of the interpretation of Oryctodromeus as adapted for digging using morphometric analyses and muscular reconstructions of the humerus, scapula, and coracoid. The morphometric analyses used two methods, including traditional morphometrics using principal component analysis of a series of element length measurements and geometric morphometrics using relative warp analysis of a series of landmarks superimposed on photographs of elements. Both methods reduce the number of variables to explain the greatest amount of variation between specimens. Results indicated that the humerus of Oryctodromeus is slightly more robust than other basal ornithopods, the coracoid exhibits no specialization for digging, and the scapula is strongly specialized, with a long narrow acromion and strongly expanded posteroventral margin of the scapular blade providing greater surface area for muscle attachment. Reconstruction of the forelimb musculature was generated by comparing both the presence or absence of muscles and the locations of attachment sites between birds and crocodilians, the extant phylogenetic bracket of dinosaur, and by examination of specimens of Oryctodromeus and other ornithopods for osteological correlates. Muscle groups used for burrowing in mammals include the deltoideus scapularis, latissimus dorsi, triceps longus, and teres major. The first three are present in Oryctodromeus, but the presence of the teres major is equivocal. The strongly expanded posteroventral scapula indicates an increased surface area for the origin of the deltoideus scapularis and possibly teres major. This expanded area would be advantageous for burrowing. The origin of the triceps longus near the glenoid of the scapula would not provide strong extension of the antebrachium, a motion important in scratch-digging. The osteology and musculature both provide evidence of slight adaptation for scratch-digging in Oryctodromeus. As many vertebrates burrow without morphological specializations, the presence of these features sufficiently supports adaptation for burrowing in Oryctodromeus.Item Taphonomic and biostratigraphic analysis of fossil freshwater turtles in the upper Cretaceous (Campanian) Kaiparowits Formation of southern Utah, USA(Montana State University - Bozeman, College of Letters & Science, 2012) Knell, Michael Jo; Chairperson, Graduate Committee: David Varricchio; Frankie Jackson, Alan Titus and L. Barry Albright III were co-authors of the article, 'A gravid fossil turtle from the upper Cretaceous (Campanian) Kaiparowits Formation, southern Utah' in the journal 'Historical biology' which is contained within this thesis.Freshwater turtles comprise a large percentage of many fossil vertebrate assemblages in western North America. The Upper Cretaceous (Campanian) Kaiparowits Formation, a thick sedimentary unit composed primarily of fluvial and floodplain deposits, is well-exposed within Grand Staircase-Escalante National Monument in southern Utah and is known for abundant fossil turtle remains. The abundance of fossil turtles may be attributed to a variety of factors including high preservation potential. The purpose if this project is to analyze the preservation potential of freshwater turtles, particularly in fluvial depositional environments, by examining the morphology of turtles in relation to transportability and the environment of deposition. It is hypothesized, for instance, that turtles with large, robust shells that were deposited in locations offering rapid burial had a greater preservation potential than those with more fragile shells and those that were exposed for longer periods of time prior to burial. Taphonomic data, including preservation quality, taxon identification, and sedimentary context, was collected for over 700 turtle specimens in both museum collections and in the field. Depositional environment was inferred for specimens with sedimentary context data. A comparison of taphonomic data shows a preservation preference towards turtles that were buried within channel deposits, but only for those with robust shells. Remains of larger turtles are common, but typically only as fragmentary remains. Small turtle taxa are all found as fragments, primarily in overbank, pond, and other floodplain deposits. An analysis of transport and deposition trends was conducted by comparing the orientation and alignment data from in situ fossil specimens to the results of a flume study using the shells from a variety of extant taxa. Results show that shells with a more highly domed carapace tend to be deposited in a carapace-up orientation. There is also a trend for oblong shells to align themselves lateral-to-flow in the channel prior to burial. Examination of alignment trends supports previous paleoflow direction estimates using sedimentary structures. An analysis of the biostratigraphic distribution of the various turtle taxa within the Kaiparowits Formation reveals no apparent change in turtle fauna during deposition of the formation.Item Postglacial vegetation, fire, and climate history of Blacktail Pond, Northern Yellowstone National Park, WY(Montana State University - Bozeman, College of Letters & Science, 2008) Huerta, Mariana Angelica; Chairperson, Graduate Committee: Cathy WhitlockPrevious studies in Yellowstone National Park (YNP) suggest intensification of the summer-dry and summer-wet patterns in Yellowstone during the early Holocene when increased summer insolation caused atmospheric circulation patterns to strengthen. To examine this hypothesis further, pollen and high-resolution charcoal records were analyzed from Blacktail Pond to reconstruct fire and vegetation histories near the present transition between summer-wet and summer-dry conditions. The site currently lies in Pseudotsuga parkland with Artemisia steppe at lower elevations around the pond. The site supported sparse tundra prior to 12,000 cal yr B.P. and fires were uncommon. Between 12,000 and 11,000 cal yr B.P, fire activity increased and Picea-Pinus parkland was established. These changes are consistent with increasing temperature and moisture. Between 11,000 and 7600 cal yr B.P., pollen evidence of a Pinus-Picea-Abies forest is consistent with increased winter moisture, while high fire activity at this time indicates that summers had lower effective moisture than at present. Between 7600 and 4000 cal yr B.P., vegetation around the site shifted to parkland dominated by Pinus, Picea, Pseudotsuga, and Artemisia indicating that effective winter moisture decreased. Fire activity continued to be high during this time suggesting summers maintained low effective moisture. The development of Artemisia steppe around the site over the last 4000 years indicates that effective winter moisture decreased, while decreased fire activity indicates that effective summer moisture increased during this time. Winter conditions during the early Holocene that resemble a summer-wet site along with summer conditions at the same time resembling a summer-dry site could be a result of the geographical setting of Blacktail Pond near the boundary between these two precipitation regimes. Poaceae/Artemisia pollen ratios were used to infer wet/dry climate oscillations during the late Holocene. The fluctuations correspond well with other paleoclimate data from northern Yellowstone National Park (Gennett and Baker, 1986; Hadly, 1996; Meyer et al., 1995), and suggest that conditions were drier from 3775-3125, 2475-2225, 1700- 675, and 425-75 cal yr B.P.